Hi all, so I went out and got a replacement febco 765 pvb because the bottom ball valve split over the winter (guess the faucet turnoff valve in the basement isn't closing all the way, but thats another story).

I threaded the new pvb onto the outlet pipe (to the sprinkler system), but ran into a problem I cannot figure out. How do I seal the inlet valve? If I turn the inlet ball valve one way, it tightens onto the inlet pipe (from the water line), but loosens the valve from the pvb itself. And If I turn it the other way, visa-versa. If the ball valve had reverse threads on one end it looks like it would work, but as it stands I cannot for the life of me figure out how to get this thing put on.

I would greatly appreciate any ideas!

Thanks!